Oil/water separators with in-situ cleaning of the oil separating plate stacks therein are now generally known in the art as disclosed for example in U.S. Pat. No. 6,659,290 B1 to Lawson et al. Current procedures for separator cleaning and for maintenance thereof are labor-intensive and also involve exposure of personnel to waste oil and cleansing chemicals utilized. Furthermore such oil/water separators involve separation limited to small quantities of oil such as 10-gallons per minute (gpm). It is therefore an important object of the present invention to provide an arrangement for the foregoing type of oil/water separator which will avoid the aforementioned disadvantages associated therewith, such as small quantity of oil separation.